Portable hardness tester



May 11, 1954 E. A. PEABODY PORTABLE HARDNEss TESTER Filed Aug. 24, 1950 1N VEN TOR.

FTTa/V/rfy Patented May 11, 1954 UNITED STATES OFFICE PORTABLE HARDNESS TESTER Edwin A. Peabody, Detroit, Mich., assigner to Paul Zaro, Detroit, Mich.

3 Claims.

This invention relates to hardness testing devices and more particularly to a hardness testing device oi' the portable type.

The present invention relates to a hardness testing device in which, like the Rockwell type of testing machine, a positive reading is obtained, but which differs therefrom in that the present device is portable. Also, with the present invention the personal equation which is present in the Scleroscope and Brinell types of instruments is eliminated.

The device of this invention is constructed to provide free fall to a hammer combined with an accurate clutch element for holding the hammer at rebound height so that scales may be read directly from a scale indicia member on the body of the device giving Rockwell, Brinell, Scleroscope, and other scale readings.

The hardness testing device of the present invention provides readings within a satisfactory degree of accuracy for shop use, thereby providing hardness readings instantly on the job.

Gne of the important objects of this invention is to provide a device of the character described comprising a minimum number of parts which may be economically manufactured and readily assembled.

Another important feature of the invention is the provision of improved means for applying or associating the scale indicia with the device whereby this indicia may be produced on a flat sheet and then wrapped around the body of the device and assembled therewith for adjustment to initially set the graduations of the scales to obtain a maximum degree of accuracy of readings.

Still another important feature of the invention is the provision of a clutch mechanism formed of plastic material, preferably of a nylonbase plastic, which is light in weight, is not soluble or deleteriously affected by oil, Water or industrial cleaners, is stable and warp-resistant, and may be easily machined.

A still further object of the invention is to provide a clutch mechanism having a shiftable part movable directly by the hammer assembly to operative and inoperative positions just prior to the completion of the striking movement and prior to the movement of the hammer assembly into latched position.

Various other objects, advantages, and novel details of construction of the invention will be made more apparent as this description proceeds, especially when considered in connection i with the accompanying drawing in which:

Figure 1 is a longitudinal, sectional, elevational view of a hardness testing device constructed in accordance with this invention;

Fig. 2 is a transverse sectional view taken substantially on the plane indicated by line 2--2 in Fig. 1;

Fig. 3 is a transverse sectional view taken substantially on the plane indicated by line 3--3 in Fig. 1;

Fig. 4 is a transverse sectional View taken substantially on the plane indicated by line 4--6 in Fig. 1;

Fig. 5 is a fragmentary elevational view as viewed from line 5-5 of Fig. 1; and

Fig. 6 is a plane view of the indicia member before being bent and assembled with the body of the device.

The hardness testing device of the present invention is of small, compact size, and in its carrying position as illustrated in Fig. 1 is readily portable. The device comprises a hollow body i0 which, in the embodiment illustrated, is of square tubular form exteriorly and made of stainless steel or like hard material having a longitudinal slot i i disposed in at least three of the four faces thereof between the enlarged upper and lower ends i2 and i3 thereof.

Mounted in a slot in the upper end l2 is a latch i@ having a pivot i5 about which it oscillates into and out of latching engagement. A spring it normally urges the latch I4 in one direction, and a knob Il is provided on the latch :for oscillating the same to unlatched position. The lower end of the latch is provided with a detent I8 for a purpose to be explained hereinafter.

The hammer assembly I9 comprises a cylindrical rod 2i] which is hardened and accurately ground and is provided with a broad arcuate striking point 2l at its lower end and a knurled Y knob Z2 at its upper end. A hammer element 23 of substantially cylindrical form is press-fitted or otherwise secured upon the rod 2E) adjacent the striking end or point 2l. The hammer element 3 is provided intermediate its ends with a circumferentially extending enlarged area 24 which is out of Contact with the bore but which guides the lower end of the hammer during its reciprocal movement permitting only line engagement therewith. The striking end 2l of the hammer extends freely through a collar 25 pressfitted or otherwise secured in the lower end portion i3 of the body. The collar 25 may be provided with V slots 2t for locating the end of the device along a bar or rod.

The hammer element 23 is formed with a circumferentially extending notch or recess 2l adapted to be engaged by the detent I8 of the latch ifi!- to retain the striking end 2| of the hammer' at a predetermined height above the collar 25 thus providing a standard length of fall for the hammer each time it is dropped. Adjacent the notch or recess 2l' the hammer element 2S is formed with a head 28 forming a shoulder 2S for a purpose to be hereinafter described. The head 2t is provided with a vernici' or indieating line 363 of a contrasting color from which readings may be directly taken in a manner hereinaiter described.

Mounted about the upper end of rod 20 is a clutch mechanism, the movable part of which is indicated generally by the reference characters 3|. The mechanism comprises a cylindrical cage portion 32 at one end, an upper sleevelike portion .'33 adapted for engagement with the knob 22, and intermediate spaced circumierentially extending shoulders forming an annular recess 35. A clutch collar is press-fitted or otherwise secured in the upper end .i2 of the body l0 and this collar is provided with annular shoulder 3l limiting movement of clutch mechanism 3i in one direction. Movement of the clutch mechanism 3l in the other direction is limited by a closure or cap member 3S secured in the open end of the end portion l2 by swaging the end wall, as shown at 38, into an annular recess formed in the closure or cap member 33.

Thus, the clutch mechanism capable of movement relative to rod il within limits defined by the shoulder 3l of collar 3S and the underface of closure member 38. Disposed in the annular recess 35 is resilient friction ring ci! which engages the inner surface of the collar 36 to hold the cage portion 32 of the clutch mechanism 3l raised position, after it has been moved to this position, by engagement of shoulder 29 with the lower end of cage 32.

The cage 32 oi the clutch mechanism is provided with a plurality of apertures di, preferably three in number, in each of which a hardened ball 'l2 is nested. The inner adjacent wall of the clutch collar Sii is provided with a conical surface i3 of such extent and diameter as to be wedgingly engaged by the balls i2 when the cage 32 is in lowered position. When the cage 32 is in raised position the balls 42 are out or wedging contact with the conical surface t3 and the rod 20.

The movable part of the clutch mechanism 3| is formed of a plastic material, preferably of a nylon-base plastic. It has been found that such a material is highly efcient because it is light in weight, is not deleteriously affected by oil, water or industrial cleaners, is stable and warpresistant and may be easily machined.

In order to facilitate the production and application of scale indicia to the device, the scales :it are etched, impressed or applied in any preferred manner to a flat sheet 45 of metal or other suitable material. This sheet is provided with slots i6 adjacent to which the scale indicia are located. The sheet l5 is also provided with a pair of slots il and a plurality of cut-away portions or notches i8 adjacent its corners. The sheet is assembled with the body il of the device by wrapping the same therearound as shown in Figs. 4 and 5, thus forming a tube 49 enclosing the body ii? with the slots l5 in registration with the slots E of the body. The tubular indicia member t9 is secured in place by rivets or the like 50 engaging the body it and the slots 4l'. The

cut-away portions 48, when the sheet 45 is assembled on the body I0, form slots 5| which receive set screws 52 threaded into the body I0. By this arrangement the tubular indicia member 49 may be adjusted longitudinally of the rivets to initially set the scales so that a maximum degree of accuracy of readings is obtained. The Vernier or indicating line 30 on the head of the hammer element 23 indicates the height of rebound relative to the scale indicia 44, the line 3l) being visible through the registering slots of the body |0 and 4'6 of the indicia member lle.

In operation, the knob 22 is grasped by the operator and is raised to elevate the hammer element 23 into latched position with the detent i3 engaging the notch 21. In this operation, the lower end 55 of the cage 32 of the clutch mechanism 3| is engaged by shoulder 29 of head 23, and the movable clutch part is moved upwardly and retained in this raised position by the frictional engagement of friction ring 4c with the inner surface of collar 36. The lower end I3 is then placed against the material to be tested and the latch |4 is released to permit a free fall of the rod 20, the hammer element 23, and the knob 22, which will occur if the body I0 is maintained in vertical position. The striking end 2i strikes the material being tested, and as a result thereof rebounds to a height conforming to the hardness of the material. Just prior to the striking of the blow the knob 22 strikes the end of the sleeve portion 33 of the clutch mechanism 3| and moves the same downwardly to the position illustrated in Fig. 1 wherein the balls 42 are in position to lock the rod 20 against downward Inovement on the cam surface 43. Therefore at the top of the rebound the balls 42 will form a wedge lock between the cam surface 43 and the rod 2Q, thereby retaining the rod substantially at the maximum point of rebound. Readings may then be taken by means of the scales 44 and the Vernier line 30 visible through the registering slots and 46. The graduations of the scales 44 may be such that readings may be made in Rockwell B, Rockwell C, Brinell, Scleroscope and the like.

With the parts fully telescoped as shown in Fig. 1, the device is compact and of a size that may be easily carried in the pocket of the operator. The device is constructed from a minimum number of parts which may be economically manufactured and readily assembled.

What is claimed is:

l. In a hardness testing device, a one-piece body having a bore extending entirely therethrough so as to be open at both ends, said body having a slot communicating with the bore disposed parallel to the axis thereof, a rod eX- tending through said bore with its upper end projecting therebeyond and with its lower end provided with a striking point having a broad arcuate face which is projectable from the lower end of the body, a hammer element of substantial mass having a central aperture through which said rod extends and to which it is secured with the striking point extending therebeyond, said hammer element being of a diameter to snugly t the body bore, a shiftable clutch mechanism mounted in the upper end of the bore for limited movement therein, and means on the rod for shifting said clutch mechanism downwardly into clutch position near the end of the fall of the rod, there being indicia on said body adjacent to said slot for indicating hardness readings.

2. In a hardness testing device, a one-piece body having a bore extending entirely therethrough so as to be open at both ends, said body having a slot communicating with the bore and disposed parallel to the axis thereof, a rod extending through said bore with its upper end projecting therebeyond and with its lower end provided with a striking point having a broad arcuate face which is projectable from the lower end of the body, a hammer element of substantial mass having a central aperture through which said rod extends and to which it is secured with the striking point extending therebeyond, said hammer element being of a diameter to snugly nt the body bore, a shiftable clutch mechanism mounted in the upper end of the bore for limited movement therein, means on the rod for shifting said clutch mechanism downwardly into clutch position near the end of the fall of the rod, a tube formed from a ilat sheet with the adjacent ends substantially abutting, having at least one slot therein with indicia adjacent thereto, said tube being disposed on the body for adjustment thereon, and means on said body by which the tube is adjusted to diierent positions for locating the indicia relative to the body slot.

3. In a hardness testing device, a one-piece body having a bore extending entirely therethrough so as to be open at both ends, said body having a slot communicating with the bore and disposed parallel to the axis thereof, a rod extending through said bore with its upper end projecting therebeyond and with its lower end provided with a striking point having a broad arcuate face which is projectable from the lower end of the body, a hammer element of substantial mass having a central aperture through which said rod extends and to which it is secured with the striking point extending therebeyond, said hammer element being of a diameter to snugly the body bore, a shiftable clutch mechanism mounted in the upper end of the bore for limited movement therein, means on the rod for shifting said clutch mechanism downwardly into clutch position near the end of the fall of the rod, and a sleeve in said clutch mechanism having a central aperture through which the rod extends and through whieh it freely falls when testing the hardness of a material, said sleeve being maple of plastic material so as not to detract substantially from the striking force of the rod when shifting the sleeve just prior to the time the rod end strikes the material to be tested.

References Cited in the iiie of this patent UNTED STATES PATENTS Number Name Date 1,444,606 Herrmann Feb. 6, 1923 1,446,620 Hall Feb. 27, 1923 l490,836 Lipps Apr. l5, 1924 1,762,639 Roudie June 10, 1930 2,288,560 Webber June 30, 1942 2,316,377 Wilhelm Apr. 13, 1943 2,427,151 Mick Sept. 9, 1947 FOREIGN PATENTS Number Country Date 33,427 France May 2, 1928 (Addition to No. 623,985) 854,464 France Jan. 19, 1940 

